Manfaat teh hijau untuk diabetesi

Penelitian tentang efek teh hijau dilakukan pada 60 orang berusia 32-73 tahun, yang kadar gula darah puasa >110mg/dL atau gula darah sewaktu >140mg/dL. Subyek dibagi 2 kelompok, kelompok pertama mendapat teh hijau (green tea-extract powder mengandung 544 mg polyphenols (456 mg catechins) setiap hari selama 2 bulan kemudian dihentikan dan diamati selama 2 bulan, kelompok kedua diamati selama 2 bulan kemudian mendapat teh hijau selama 2 bulan.

Hasil penelitian menunjukkan penurunan signifikan kadar HbA1c dan penurunan tekanan darah diastolik. Kesimpulan untuk pra-diabetesi, minum teh hijau setiap hari dapat menurunkan kadar gula darah.

Original Article

European Journal of Clinical Nutrition (2008) 62, 953–960;

Randomized controlled trial for an effect of green tea-extract powder supplementation on glucose abnormalities

Y Fukino¹, A Ikeda², K Maruyama^1,2, N Aoki³, T Okubo⁴ and H Iso²

1. ¹Department of Nutritional Sciences, School of Food and Nutritional Sciences, University of Shizuoka, Suruga-ku, Shizuoka-shi, Japan
2. ²Public Health, Department of Social and Environmental Medicine, Graduate School of Medicine, Osaka University, Suita-shi, Osaka, Japan
3. ³Department of Public Health, Hamamatsu University School of Medicine, Hamamatsu-shi, Japan
4. ⁴Central Research Laboratories, Taiyou Kagaku Co. Ltd., Yokkaichi, Mie, Japan

Correspondence: Dr Y Fukino, School of Food and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka-shi 422-8526, Japan. E-mail: fukino@u-shizuoka-ken.ac.jp

Objective:

We examined whether green tea-extract powder supplementation improves glucose abnormality.

Methods:

The study was conducted for volunteers who resided in eastern communities of Shizuoka Prefecture and who had fasting blood glucose levels of 6.1 mmol/l or nonfasting blood glucose levels of 7.8 mmol/l in a recent health check-up. Sixty subjects aged 32–73 years (49 males and 11 females) participated in the trial. The Early intervention group consumed a packet of green tea-extract powder containing 544 mg polyphenols (456 mg catechins) daily for the first 2 months and then entered the 2-month nonintervention period. The Later intervention group was observed for the first 2 months and then consumed green tea-extract powder as described above for the subsequent 2 months. Using the two-period crossover design, we analyzed the changes in fasting hemoglobin A1c level and other biomarkers in blood samples collected at baseline, 2 months and 4 months.

Results:

A significant reduction in hemoglobin A1c level and a borderline significant reduction in diastolic blood pressure were associated with the intervention. The intervention caused no significant changes in weight, body mass index, body fat, systolic blood pressure, fasting serum glucose level, homeostasis model assessment index, serum lipid level or hypersensitive C-reactive protein.

Conclusion:

Daily supplementary intake of green tea-extract powder lowered the hemoglobin A1c level in individuals with borderline diabetes.